Fix serving_advanced.md (tensorflow#740)

Author: mrkm4ntr

tensorflow_serving/g3doc/serving_advanced.md

@@ -165,8 +165,8 @@ that monitors cloud storage instead of local storage, or you could build a
 version policy plugin that does version transition in a different way -- in
 fact, you could even build a custom model plugin that serves non-TensorFlow
 models. These topics are out of scope for this tutorial. However, you can refer
-to the [custom source](custom_source.md) and [custom servable]
-(custom_servable.md) tutorials for more information.
+to the [custom source](custom_source.md) and
+[custom servable](custom_servable.md) tutorials for more information.
 
 ## Batching
 
@@ -250,7 +250,7 @@ To put all these into the context of this tutorial:
     servables that can be loaded.
 
   * `AspiredVersionsManager` monitors the export stream, and manages lifecycle
-    of all SavedModelBundle` servables dynamically.
+    of all `SavedModelBundle` servables dynamically.
 
 `TensorflowPredictImpl::Predict` then just: